Health related quality of life (HRQL) is a key, patient-centered outcome in lung transplantation. While HRQL may improve following transplantation, available data indicate that HRQL remains well below that of the general population. In theoretical models of disablement, the domain of functional limitation leads to disability and both are precursors to and, therefore, "upstream" determinants of HRQL. To date, the determinants of HRQL and the role of persistent limitations and associated disability in the HRLQ limitations following transplant have not been elucidated. The central study hypotheses are that patients with end-stage lung disease will suffer from functional limitations, disability, and poor HRQL and that following transplantation, both pulmonary and non-pulmonary organ dysfunction, associated in part with therapies required to preserve graft function, will account for residual functional limitations, ongoing disability, and persistently reduced HRQL. A prospective cohort study is proposed to assess functional limitations, disability, and HRQL in patients with end-stage lung disease before and after lung transplantation. Prior to transplantation, subjects will complete a structured survey assessing functional limitations, disability, HRQL. In addition, tests of lung function, exercise capacity (6 minute walk test), and lower extremity strength will be performed. Supplemental data related to the disease indication for transplantation, disease severity and comorbidities will be extracted from medical records. Key measures will be repeated at 3, 6, and 12 months after lung transplantation. Baseline data will be used as follows: to elucidate the impact of end- stage lung disease on functional limitation, disability, and HRQL on patients awaiting lung transplantation. Longitudinal data will be used as follows: to assess the impact of lung transplantation on measures of functional limitation, disability, and HRQL and to identify sources of persistent or new limitations or disabilities that may affect HRQL. We intend to study 30 subjects using repeated measures analysis and allowing for sufficient study power to detect an 0.5 SD change (consistent with a clinically meaningful difference) in key outcome measures. PUBLIC HEALTH RELEVANCE: Characterizing how lung transplantation enables or does not assist patients with end-stage lung disease to return to participating in activities they rate as meaningful (valued life activities) should provide valuable information to patients, their families, and health care providers coping with post- transplantation management. Moreover, elucidating the causes of functional limitations and disability following transplant may identify new areas for intervention that may lead to improved outcomes, in particular HRQL.